MARITIME – PROPULION & PERFORMANCE CALCULATOR
Froude Number
A precise tool.
What is the Froude Number & How does it work?
The Froude number (Fr) is a dimensionless parameter that compares a ship’s inertial forces to the gravitational forces acting on the water surface.
It is especially useful for predicting wave‑making resistance and estimating the theoretical hull speed, because wave patterns are governed by the balance between kinetic energy and gravity.
Naval architects use the Froude number to assess performance across different hull forms and to scale model test results to full‑size vessels.
Fr = \frac{V}{\sqrt{g L}}
Fr = Froude number
V = ship speed (m/s)
g = gravitational acceleration (9.81 m/s²)
L = waterline length (m)
V = ship speed (m/s)
g = gravitational acceleration (9.81 m/s²)
L = waterline length (m)
Parameters
Result
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Frequently Asked Questions
What is the Froude number used for in naval architecture?
The Froude number helps naval architects predict wave-making resistance and estimate theoretical hull speed by comparing inertial forces to gravitational forces.
How do you calculate the Froude number?
The Froude number is calculated as Fr = V / √(g * L), where V is the ship's velocity, g is the acceleration due to gravity, and L is the characteristic length of the vessel.
Why is the Froude number important for model testing?
The Froude number allows naval architects to scale model test results accurately to full-size vessels by ensuring similar wave patterns in both models and prototypes.
What does a high Froude number indicate about a ship's performance?
A high Froude number indicates that the ship is operating at higher speeds relative to its length, which can affect wave-making resistance and overall performance.
Can the Froude number be used for different hull forms?
Yes, the Froude number is a dimensionless parameter that can be used to assess performance across various hull designs and shapes.
Results are for informational purposes only and do not constitute professional advice.